Service in a communications network

ABSTRACT

A call from a calling party to a first called party in a telecommunications network is initiated via a network switch. Subsequently a leg of the call from the network switch to the first called party is released. Data identifying a second called party is transmitted from the first called party to a network control platform. The network control platform correlates the data transmitted and the respective call earlier made and controls the network switch to now route the earlier call to the second called party.

BACKGROUND TO THE INVENTION

1. Field of the Invention

The present invention relates to a communications network, and inparticular to a network in which a party at the edge of the networktakes a call and subsequently transfers the call to another party.

2. Related Art

Commonly, service providers in a network such as the PSTN (PublicSwitched Telephony Network) need to take a call from a calling party,carry out some transaction with the calling party and then route thecall to another number. For example, BT operates a service known as ACEwhich uses a voice recognition platform to provide customers withinformation relating to their telephone bills. After the customer hasreceived the relevant information, they are offered the option of beingconnected to a human operator. If the customer takes up this option, theplatform then needs to route the call to the appropriate number for thehuman operator. This operation of taking a call at one number andsubsequently routing it to another number is known as take back andtransfer. Hitherto, take back and transfer has been implemented usingswitched-based three party services. The service provider has a switchfunction within their service platform. This switch function is used toroute the incoming call onwards to the new destination. This approach,which is known as tromboning, has a number of disadvantages. Onedisadvantage is that the called customer is responsible for the paymentof the second leg of the call. A further disadvantage is that twocircuits in the telecommunications network are tied up for the durationof the call.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda method of operating a telecommunications network comprising:

(a) initiating a call from a calling party to a first called party via anetwork switch;

(b) subsequently releasing a leg of the said call from the networkswitch to the first called party;

(c) transmitting from the first called party to a network controlplatform data identifying a second called party;

(d) at the network control platform:

i. correlating the data transmitted in step (c) and the respective callmade in step (a).

ii. controlling the network switch to route the call initiated in step(a) to the second called party.

The present invention provides a new way of implementing a take back andtransfer function. This is done in such a way that it can be controlledfrom the edge of the network without requiring any special equipment atthe first called party, who typically may be a service provider. Theservice can be invoked simply using a normal telephone, or, for example,by minor modifications to control scripts running on an IVR (intelligentvoice response) platform. At the same time, the method avoids having twocircuits tied up simultaneously, and also ensures that the entire costof the call is billed to the calling party. These advantages areachieved by controlling a network switch to release the leg of the callfrom the switch to the first called party once the transactions betweenthe calling party and the first called party are completed. Then in aseparate communication from the called party to a network control, thefirst called party communicates the identity of the number to which thecall is to be transferred. The network control platform correlates thisinformation with the original call and connects the call through to thefinal destination.

The information transmitted in step (c) may be communicated to thenetwork control platform via a data communications network. For example,the service provider may have an Internet connection to the serviceplatform and may transfer the necessary data in this way. Preferablyhowever in step (c) the data is transmitted by making a call from thefirst called party to the network control platform via thetelecommunications network. This preferred approach has the advantagethat the first called party then needs no additional equipment orinterfaces.

Preferably the telecommunications network has an IN (IntelligentNetwork) architecture, and the network control platform is a servicecontrol point.

The present invention is particularly effective when implemented usingIN technology. Then the intelligence for the network control platformmay be located at one or more service control points which then armrespective switches or service switching points (SSP) to detect theappropriate points in the call.

Preferably in step (a) the call is registered at the network controlplatform. In this preferred implementation, the call is registered atthe outset at the network control platform. The control platform is thenprimed to detect the release of the call by the first called party, andthen to hold, pending receipt of data identifying the second calledparty, the first leg of the call from the calling party to the networkswitch.

Preferably on the said leg of the call being released in step (b) thenetwork control platform starts a timer, and the leg of the call fromthe calling party to the network switch is held until the said timer hasexpired.

According to a second aspect of the present invention, there is provideda network control platform for use in a method in accordance with thefirst aspect, the network control platform comprising:

means for registering a call initiated by a calling party via a networkswitch to a first called party;

a signalling interface for receiving from the first called party dataidentifying a second called party;

means for correlating the data received from the first called party anda call registered by the said means for registering; and

control means responsive to the said means for correlating and arrangedto output a control signal to cause a network switch to switch the callto a second call party.

Preferably the network control platform further comprises means fordetecting when a call registered in the means for registering isreleased by the first called party; and

a timer responsive to the said means for detecting;

in use the network control means holding a leg of a call registered inthe means for registering until the said timer has timed out.

BRIEF DESCRIPTION OF THE DRAWINGS

Methods and apparatus embodying the present invention will now bedescribed in further detail, by way of example only, with reference tothe accompanying drawings in which;

FIGS. 1a and 1 b are schematics of prior art networks;

FIG. 2 is a schematic of a first network embodying the presentinvention;

FIG. 3 is a schematic of a second network embodying the presentinvention with message flows indicated;

FIG. 4 is a schematic of a further alternative embodiment; and

FIG. 5 is a schematic showing in further detail a network controlplatform for use in a network embodying the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1a shows the steps involved in a prior art take back and transferfacility and FIG. 1b indicates the path taken by the resultingthree-party connection. In this prior art system, a calling party Amakes a call via a network switch to a service provider. An applicationB running on a service provider; platform carries out a transaction withthe calling party. At the completion of this transaction, in order totransfer the call, the service provider platform makes an enquiry callvia the network switch to a second called party or “termination” partyC. While this enquiry call is made, the incoming call is held by theservice provider. Subsequently, the service provider transmits atransfer request to the network switch. As a result of this transferrequest, a connection is established via the network switch and theservice provider platform to the termination C. This form of connectionis known as “tromboning” since, as can be seen in FIG. 1b, the resultingcircuit connection has the appearance of a trombone slide.

FIG. 2 shows schematically the operation of a network embodying thepresent invention. The network is conveniently embodied in a system inwhich control intelligence is separated from the network switch and islocated in a service control point (SCP). As in the previous example,the calling party initially makes a call to the service provider. Nowhowever, when the transaction with the service provider is completed,the call is released by the service provider. While the leg of the callfrom the calling party A to the network switch is still being held, theservice provider B communicates to the service control point (SCP) theidentity of the termination party C. The service control point controlsthe network switch accordingly to route the call directly from A to C.

FIG. 3 illustrates in detail the procedures outlined above with respectto FIG. 2. The network of FIG. 3 includes two network switches termedSSP (service switching points), two service control points termed NIP(network intelligence platforms) and a global data server (GDS) which isconnected in common to all the NIPs by a wide area network (WAN).

The method will now be described with reference to the message flowsindicated on the Figure. Initially, caller A calls the number of theservice provider and a set-up message is sent to a local SSP(1). Aninitial DP operation (2) as defined in INAP (intelligent networksapplication protocol) is sent from the SSP to that NIP which isassociated with the SSP. Within the NIP, the service number dialled bycaller A is used to select a call plan (3) that includes a servicefeature SF designed to implement the take back and transfer (TB&T)method of the present invention. The NIP then sends aRequestReportBCSMEvent (4) to the SSP. This arms an Event DetectionPoint (EDP) for O_Disconnect (Interrupted). O_Disconnect is one type ofevent which can be armed within the INAP protocol. It can be armedindependently on both the calling and called parties of the call. Thisevent is activated when the chosen party of the call initiates theclearing of the call (from their end). In this example, we arm the eventon the called party (leg 2/B party). This is to detect when the firstcalled party clears. INAP events can be armed in either Interrupted orNotify mode. Interrupted means that when the event is activated the SCPregains control of the call, allowing further actions to be performed onthe call. Notify mode simply indicates that the event has occurred, butthe call progresses without the SCP regaining control. In the context ofthe O_Disconnect event, arming it as interrupted stops the call fromautomatically ending as a result of the called party hanging up. Thisthen allows a new called party to be connected to the caller using theINAP connect operation.

An INAP Connect operation (5) is used to route the call to the serviceprovider at the destination number associated with the service feature.

Once the call has been connected to the service provider, the relevantservice is carried out (6). For example, an interactive voice response(IVR) platform located at the service provider may play to the customera spoken menu of options, for example for different account enquiries.As part of the menu, or subsequently at a later stage in the operationof the service, the customer is offered the option of being connected toa human operator located at a different site in the network. When thisoption is taken up, then the take back and transfer function is used totransfer the call to called party C, as described below.

The service provider releases the call (7). This triggers the previouslyarmed detection point at the SSP, and causes an EventReportBCSMEvent tobe sent back from the SSP to the NIP(8). The NIP starts a timer (Ttbat)and sends a holdCallRequest message (9) to the global data server (GDS).This message contains the termination number of the service provider.The NIP sends a ReleaseCallPartyConnection operation to the SSP. The SSPis then in the waitingForInstructions state and, in accordance with theINAP protocol, the NIP is allowed to hold the call in this state for upto six seconds. If six seconds is not long enough for a second call tobe made and to be correlated with the first call, then thewaitingForInstructions timer may be extended by using an INAPResetTimer. A ResetTimer message is sent from the NIP to the SSP. In analternative embodiment, instead of the SSP being left in thewaitingForInstructions state, the SSP connects the call to anintelligent peripheral (IP) which plays an announcement to the callingparty. In this case there is no intrinsic limit on the time for whichthe call is held.

If the timer Ttabt expires, it is assumed that the TB&T service is notrequired for this call (10). The call is released and acancelHoldCallRequest is sent to the global data server. Similarly, ifthe calling party clears before a connection to called party C has beenestablished, the cancelHoldCallRequest is sent to the global dataserver. Otherwise, the service provider initiates a new call (11). Thisis to a dedicated service number, and may be either a free call or apaid call depending on the billing arrangements for the service. Theservice number dialled by the service provider includes the identity ofthe destination to which the held call is to be routed. This destinationnumber may be included explicitly. For example, the service providermight dial 0800 123 01473 648174, where “0800 123” is the number for theservice and “01473 648174” is the number for called party C.Alternatively, the service provider may, during a set-up procedure forthe TB&T service, register with the NIP a number of destination numberswhich are to be used with the service. The NIP then returns to theservice provider 4-digit identification codes which are used toreference the different destination numbers. For example, destination01473 648174 may have reference code 0001. In this case, the serviceprovider dials 0800 123 0001.

The call from the service provider triggers at the SSP which is local tothe service provider and an InitialDP (initial detection point) event(12) is sent to the NIP associated with the SSP. This may be, as in thepresent example, a NIP other than the NIP which is holding the originalcall. The receiving NIP identifies the correlation service number, i.e.0800 123, and sends a correlateHeldCallIndication to the global dataserver together with the CLI (calling line identity) of the serviceprovider and the destination number or reference code sent by theservice provider.

The global data server, on receiving the correlateHeldCallIndicationfrom the SSP searches for a heldCall by matching the CLI of the callfrom the service provider and the service provider number dialled by theuser in originating the first, held call. If a correlated held call isfound, then a routeHeldCall Indication (13) is sent to the servicefeature in the original NIP. The service feature, on receiving therouteHeldCall Indication, cancels the Ttbat timer and issues a Connectoperation (14) to the terminating number (C party). This completes thetransfer of the call.

The second NIP receives a correlatedHeldCallConfirmation from the GDSand either sends a ReleaseCall operation (15) to the service provider(triggering a confirmation tone or announcement played to the serviceprovider, or alternatively uses an Intelligent Peripheral (IP) to playan announcement, e.g.: “your call has been transferred to 01473 48174.Thank you”.

The take back and transfer service feature is not limited to uses as astand-alone service, but may be used together with other servicefeatures to produce a complex call plan. Also, while in the aboveexample the first call is answered by the service provider, this neednot be the case. The service provider might respond to the first call bysupplying another destination number in the manner described above, butwithout first answering the call. This mode of operation would beappropriate, for example, when the service provider was operating atelemarketing call centre. The call centre then is able to distributethe calls to agents without first answering the call or otherwiseprompting the caller, so that the call distribution process istransparent to the caller.

The service provider may be billed either through the billing associatedwith the TB&T plan, or via retail rates invoked when the serviceprovider issues the correlation call request. INAP “Furnish ChargingInformation” messages are sent from the NIP to the relevant SSP, both inrespect of the TB&T plan and for the call from the service provider. AnINAP “Set Charging Information (SCI)” message is used to control therate of charging and may be used, for example, to make the call from theservice provider free.

FIG. 4 shows an alternative embodiment. In this embodiment, callingparty A makes a call via the SSP to a service provider B, as describedpreviously. After executing the appropriate service application at theservice provider platform, the service provider communicates a requestfor the call to be transferred to party C. This request is transmittedto the SCP via a data communications network. In the present examplethis data communications network is the internet and the communicationis received at a TCP/IP interface 42 in the SCP. The request includesboth the identity of party C, and data, such as the PSTN CLI, whichidentifies platform B. As in the previously described example, this datais used to correlate the request with the corresponding held call fromparty A. The SCP then causes the call to be switched to party C.

Other alternative implementations are possible. For example, the initialcall from party A to the service provider might be made via theinternet, with only the final connection between A and C being made viathe PSTN.

FIG. 5 shows in further detail the structure of the NIP used in theimplementation discussed above. A service management server is connectedvia an FDDI optical fibre LAN to an overload control server (OCS) and totransaction servers (TS). The transaction servers implement advancedservice control functions such as the take back and transfer (TB&T)feature described above. The OCS and transaction servers are connectedvia a second FDDI LAN to communications servers (CS) which are connectedto the SS7 (ITU Signalling System no. 7) signalling network.

What is claimed is:
 1. A method of operating a telecommunicationsnetwork having an intelligent network service control point, said methodcomprising: (a) initiating a call from a calling party to a first calledparty via a network switch; (b) subsequently releasing a leg of the saidcall from the network switch to the first called party; (c) thentransmitting from the first called party to a network control platformof an intelligent network service control point data identifying asecond called party; (d) at the network control platform; i. correlatingthe data transmitted and the respective initiated call, ii. controllingthe network switch to route the earlier initiated call to the secondcalled party.
 2. A method as in claim 1, in which the data istransmitted by making a call from the first called party to the networkcontrol platform via the telecommunications network.
 3. A method as inclaim 1, in which the data is communicated to the network controlplatform via a data communications network.
 4. A method as in claim 1further including: arming an interrupted detection point for detecting adisconnect event caused by the first called party, and holding a leg ofthe call from the calling party to the network switch as the leg of thecall from the network switch to the first called party is released inresponse to the disconnect event.
 5. A method as in claim 1, in whichthe initiated call is registered at the network control platform.
 6. Anetwork control platform for use in a telecommunications network havingan intelligent network service control point said network comprising:(a) means for initiating a call from a calling party to a first calledparty via a network switch; (b) means for subsequently releasing a legof the said call from the network switch to the first called party; (c)means for then transmitting from the first called party to a networkcontrol platform of an intelligent network service control point dataidentifying a second called party; (d) means at the network controlplatform: i. correlating the data transmitted and the respectiveinitiated call, ii. controlling the network switch to route the earlierinitiated call to the second called party; the network control platformcomprising: means for registering a call initiated by a calling partyvia a network switch to a first called party; a signalling interface forreceiving from the first called party data identifying a second calledparty; means for correlating the data received from the first calledparty and a call registered by the said means for registering; andcontrol means responsive to the said means for correlating and arrangedto output a control signal to cause a network switch to switch the callto a second call party.
 7. A platform as in claim 6 further comprising:means for detecting when a call registered in the means for registeringis released by the first called party; and a timer responsive to thesaid means for detecting; wherein the network control means holds a legof a call registered in the means for registering until the said timerhas timed out.
 8. A service platform for use in a telecommunicationsnetwork having an intelligent network service control point said networkcomprising: (a) means for initiating a call from a calling party to afirst called party via a network switch; (b) means for subsequentlyreleasing a leg of the said call from the network switch to the firstcalled party; (c) means for then transmitting from the first calledparty to a network control platform of an intelligent network servicecontrol point data identifying a second called party; (d) means at thenetwork control platform: i. correlating the data transmitted and therespective initiated call, ii. controlling the network switch to routethe earlier initiated call to the second called party; said serviceplatform comprising: a) means for receiving a call from a calling partyb) means for executing a service application in response to the saidcall; and c) means for communicating to a network control platformremote from the said service platform a request for routing the saidcall to another party.
 9. A method of operating a telecommunicationsnetwork having an intelligent network service control point, said methodcomprising: (a) initiating a call from a calling party to a first calledparty via a network switch; (b) subsequently releasing a leg of the saidcall from the network switch to the first called party; (c) thentransmitting from the first called party to a network control platformof an intelligent network service control point data identifying asecond called party; (d) controlling the network switch to route theearlier initiated call to the second called party.